Thomas Davis injured his knee during the second game of the season. An MRI would later reveal his third ACL tear on the same knee. Despite his ultimately unsuccessful attempts to come back from ACL reconstruction on two prior occasions, Davis thinks he is going to make history.

Dr. James Andrews performed his most recent surgery and instead of using tendons from the apparently broken down knee, "Andrews took the patellar tendon from Davis' left knee to rebuild his right ACL. The knee is solid as a rock," Davis said. "Those were (Andrews') words."

According to the Panthers' trainer, Ryan Vermillion, no player has ever returned from three ACL reconstructions to the same knee. Davis is using the challenge to motivate himself as he rehabs. Also motivating him is the likelihood that the Panthers cut him before he is due an $8 million bonus on March 14. "The popular thinking is the Panthers will cut Davis rather than pay the bonus, and bring him back on a deal with much less guaranteed money."

This is just one of many similar stories in the NFL. While the specific details change from the player to player, the theme is constant. A player perpetually runs the risk of not only physical injury but unemployment—or at least in this case—receiving much, much less money than initially agreed upon. It's a difficult balance to achieve when the one commodity owners and fans depend on can be rendered useless so easily without a moment's notice. Football is the one sport where it simultaneously makes no sense and all the sense in the world that contracts are not guaranteed.